S. Mahunka szerk.: Folia Entomologica Hungarica 62. (Budapest, 2001)

Unexpected occurrence of Plocamaphis flocculosa (Weed, 1891) (Homoptera: Aphididae); new subspecies to Hungary with new host plant A Plocamaphis flocculosa (Weed, 1891) (Homoptera: Aphidae) váratlan előfordulása: új alfaj új tápnövénnyel a magyar faunában Összefoglalás — A Plocamaphis flocculosa brachysiphon Ossiannilsson, 1959 a magyar faunára új alfaj. A példányokat Salix alba ágain gyűjtöttek. Ez a fűz eddig nem volt ismeretes a faj tápnövényei között. Plocamaphis Oestlund, 1922 is a small genus of Sa/á-feeding aphids which has only five species in the world. These species are less hairy than the species belonging to the related genus Pterocomma. The species of Plocamaphis secrete flocculent wax and they are not attended by ants. Two Plocamaphis species live in Europe: Plocamaphis amerinae (Hartig, 1841) and Plocamaphis flocculosa (Weed, 1891). The European populations of the latter species are variable. They are subdivided into four subspecies. One of them, P. f. flocculosa, has nearctic distribution. Three European subspecies of P. flocculosa have been distinguished by Ossiannilsson, cited by Heie (1986) doubting that these are valid taxonomic categories. According to Heie further work is required to determine whether the characters employed for separation of the subspecies are of any diagnostic value. He found that the differences between these subspecies were very small and not diagnostic. However, Heie studied only a few specimens of P. f. flocculosa and/ goernitzi Börner, 1940. The apterous viviparous female of P. flocculosa is grey or yellowish grey with orange siphunculi, 3.1-5.0 mm long, densely covered with wax powder. The distinction of the subspecies is based on the rate of siphunculus and the second segment of hind tarsus. According to the identification key of Ossiannilsson the rate of the siphunculus and the second segment of hind tarsus is 1.1 times or shorter (0.8-1.1 times) in the case of P. f. brachysiphon Ossiannilsson, 1959 (apterous viviparous female). The same rate is 1.25-1.5 times by P. f. goernitzi and 1.5 times or longer by P. f. macrosiphon Ossiannilsson, 1959. These subspecies were recorded from the following countries: P. f. brachysiphon has been found in Sweden, Great Britain, The Netherlands, Germany (not in N Germany), Poland (not in the Baltic region); P. f. goernitzi lives in Sweden, Finland, Belgium, France, Germany (not in N Germany), Poland (not in the Baltic region), Hungary; P. f. macrosiphon is known only from Sweden. Hungary is the most south-eastern point of the distribution of P. flocculosa and P. f. brachysiphon subspecies. The recorded host plants ofP.f. brachysiphon are Salix cinerea, S. caprea and S. repens. The subspecies P. f. goernitzi lives on branches of Salix cinerea and S. caprea. Whilst the third subspecies, P. f. macrosiphon, lives probably on Salix dasyclada. in 1999, aphid colonies were sampled from dispersed willow trees (Salix alba) near Kiskőrös, in Hungary. 33 trees were investigated every two weeks from April till November (15 surveys). More than 62,000 specimens were collected and identified. We collected 667 individuals of P. flocculosa from the end of September till the middle of November, and we found two apterous viviparous female on 1st of June. These specimens occurred on twigs and branches of only on two tree individuals. We counted 58